In general, a hydraulic excavator as a representative example of construction machines is configured with an automotive lower traveling structure, an upper revolving structure that is mounted on the lower traveling structure to be capable of revolving thereon and a front device that is mounted on the upper revolving structure to be capable of tilting and lifting thereto.
The upper revolving structure of the hydraulic excavator comprises a vehicle body frame that is formed as a support structure, a counterweight that is provided to extend in a left-right direction of the vehicle body frame in the rear end to the vehicle body frame for acting as a weight balance to the front device, an engine that is positioned in the front side to the counterweight and is mounted on the vehicle body frame in a horizontal state of extending in the left-right direction, a hydraulic pump that is provided in the engine to be positioned in one side of the left-right direction of the vehicle body frame, an exhaust gas post-treatment device that is connected to an exhaust gas side of the engine to be positioned above the hydraulic pump and performs post-treatment of an exhaust gas discharged from the engine, a firewall that is provided as a partition between an engine room in which the engine and the exhaust gas post-treatment device are arranged and a pump room in which the hydraulic pump is arranged, a cooling fan that is provided in the engine room to be positioned on the other side of the left-right direction of the vehicle body frame and sucks in outside air as cooling air, a heat exchanger that is provided on the vehicle body frame to face the cooling fan and cools fluid by the sucked cooling air, and an exterior cover that is positioned in front of the counterweight to cover the engine, the hydraulic pump, the exhaust gas post-treatment device and the heat exchanger (Patent Document 1).
Here, when the hydraulic excavator is activated to rotate the cooling fan, the outside air is supplied to the heat exchanger through an opening of the exterior cover. Thereby, the heat exchanger can cool fluid such as engine cooling water and hydraulic oil with the cooling air by the cooling fan.